Roller boring drill



1938. R. w. SCHLUMPF -r AL 2,104,819

ROLLER BOR ING DRILL Filed March 9 1935 Haber? Z4). 'cZzl um pf 5 Ragviz P. Sherman INVENTOR ATTORNEY Patented Jam-11, 1938 ROLLER BORINGDRILL Robert W. Schlumpf and Ralph P. Sherman,

Houston, Tex., assignors to Hughes Tool Company, Houston, Tex., acorporation of Texas Application March 9,

2 Claims.

Our invention relates to roller boring drills such as are employed indrilling deep wells for oil, gas, sulphur and the like.

The improvement consists in the provision of an effective type ofbearing forthe rolling outters.

The invention is particularly applicable to cutters upon the so-calledcone cutters employed in hard formation bits.

It is an object of the invention to provide a bearing surface uponthecutter shaft which may have a rotation with the cutter upon the shaftbut at a slower rate of rotation than that of the cutter itself, thusallowing a smooth rotation of the cutter and a prolonged life upon thebearing.

We desire to provide a form of anti-friction bearing which will be ofstrong and sturdy construction and not liable to become broken in use.We wish to avoid the difiiculty commonly experienced with rollerbearings where said bearings will be broken and moved out of positionduring the operation of the cutter.

In the drawing, Fig. 1 is a side view partly in elevation and partly incentral vertical section showing one embodiment of the invention.

Fig. 2 is a broken sectional detail showing a cutter upon its shaft witha slightly different form of bearing.

Fig. 3 is a view similar to Fig. 2 but illustrating a still differentembodiment of the invention.

Figs. 4 and 5 are perspective views of the bearing members removed fromtheir position upon the shaft.

We have illustrated the invention as applied to the usual type ofso-called cone bit. Said bit has a head i with an upwardly tapered andthreaded shank 2 for attachment to a drill collar. Said head has twodownwardly diverging legs 3, the inner faces of which are inclinedupwardly 40 and inwardly and have an integral shaft 4 there- 'on. Saidshaft projects downwardly and inwardly at approximately right angles tothe plane inner face of the leg upon which it is formed.

The head has a longitudinal passage 5 therethrough to conduct flushingfluid to the cutters in the usual manner.

The shafts 4 are shown as having an upper cylindrical area 6 of strongconstruction and a forward projection I thereon of smaller diameter.

The general form of the shaft is therefore a tapered one conforming tothe general contour of the conical shaped cutter 8 which is mountedthereon.

The cutter 8 is toothed in the-usual manner and has its inner bearingsurface shaped to conform to the shape of the shaft 2.

1935, Serial No. 10,257

The bearings between the cutter and the shaft which form the subjectmatter of our invention include a row of balls 9 fitting within theraceway partly within the shaft and partly within the inner wall of thecutter shell. These balls are 5 introducedinto the raceway when thecutter is mounted upon the shaft through a transverse opening in thehead. Said opening is closed thereafter by a plug l0 held in place by abond of welding material ll. Toward the forward end of the cutter shaftwe employ a thin sleeve l2 of bearing metal separating the cutter fromthe shaft and conforming in shape to the outer surface of the shaft. Itsinner end is of enlarged diameter, fitting over the body 4 of the shaftand the forward end is reduced to engage closely but rotatably upon theprojection 1. This bearing member forms a sleeve or thimble which isrotatable upon the shaft and also relative to the cutter. The bearingsleeve may be made of any desired metal resistant to wear such ascarburized steel and it is intended to increase the life of the cutterand the shaft during the operation of the 'bit.

It is contemplated that when the bit is operated the cutters will rollon the bottom of the hole, thus rotating upon the cutter shaft. Thebearings 9 will take up the thrust of the cutter at the outer endthereof. The bearing sleeve i2- will rotate partly with the cutter andthere will be relative movement between the cutter and the bearingsleeve and also between the bearing sleeve and the shaft. There willthus be less wear upon the cutter and the sleeve will be of sufficientlystrong and sturdy construction that it will not break up in use.

The common difliculty with cutters of this kind, that bearingsintroduced between the forward end of the cutter and the shaft willcrack up and interfere with the operation of the cutter, will be largelyeliminated.

In Fig. 2 the structure is approximately the same as in Fig. 1 with theexception of the bearing sleeve. In this particular embodiment weprovide two separate rings or sleeves l3 and I4 45 between the interiorof the cutter shell and the outer surface of the shaft. The sleeve I3 isset within a recess in the shaft and is supported upon the forward endof the large portion of the shaft. 50 The ring I4 is fitted over theprojection 1' upon the shaft and is of materially smaller diameter. Thetwo bearings are both of them rotatable upon the shaft and in use willwear on both their outer and inner surfaces, thus allowing a freer 55rotation of the cutter but also serving to form a substantial supportnot liable to break in use.

In Fig. 3 is a still diflerent embodiment. The

shaft 4' has an annular recess l5 adjacent the base of the shaft toreceive a row of rollers IE to support the cutter at that point. Theretaining row of balls I! is placed forwardly on the shaft from theroller raceway, these ballsbeing inserted through an opening closed bythe plug I 0, as previously described. The forward reduced end 1" uponthe shaft has an annular recess I 8 to receive a bearing ring i9. Saidring is divided longitudinally, as shown in Fig. 5, so that it may befitted over the end of the shaft and within the groove la.

The operation of this hearing is similar to those previously described,the rollers and balls serving in the usual manner to provide anantifriction bearing for the shaft along its larger diameter. On thesmaller diameter of the projection 'l" the ring l9 operates to provide areduced friction at that point being rotatable partly with the cutterupon its seat within the recess IS. The ring is thus able to reducefriction at the forward portion of the shaft and still be of suchconstruction that it will not break up under the extreme pressures towhich it is subjected in use.

In Fig. 4 we have shown how the bearing sleeve may if desired be formedwith perforations 28 to receive lubricating material. It is customary inthe mounting of the cutter upon the shaft to thoroughly cover thebearings with a heavy lubricant. The provision of the openings in thebearing sleeves provides still further space into which .even wheresubmitted to heavy pressures.

the lubricant may be received and decrease the friction of operation tosome extent. It is to be noted that the cutter is spaced slightly fromthe shaft except where it rests upon the bearings to thus permit thecirculation of water from the hole around, the bearings and keep themcooled during operation. It will be seen that our form of bearing issuch that it can not be easily broken The usual difliculty of having thebearings toward the forward end of the shaft broken under the heavystrains encountered will be overcome to a large extent and the life ofthe bearing materially prolonged.

What we claim as new is: i

1. A drill head, a forwardly inclined cutter shaft thereon, a cutterenclosing the end of said shaft, anti-friction bearings for said shaftacting also to retain said cutter on said shaft, a reduced forwardextension on said shaft, an annular raceway recessed in said extensionand a longitudinally divided ring of bearing material in said raceway,the end walls of said recess limiting longitudinal movement of saidring.

2. A well drill head, a cutter shaft thereon, a reduced extension onsaid shaft, a cylindrical recess on said extension, a cutter enclosingthe end of said shaft and extension, means to retain said cutter on saidshaft, and a bearing ring on said extension fitting behind a shoulder ofsaid recess thereon, and rotatable relative to said shaft and saidcutter.

ROBERT W. SCI-ILUMPF.

RALPH P. SHERMAN.

